On Wed, 2020-08-26 at 13:17 +0200, Thomas Gleixner wrote: > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > > The arch_.*_msi_irq[s] fallbacks are compiled in whether an architecture > requires them or not. Architectures which are fully utilizing hierarchical > irq domains should never call into that code. > > It's not only architectures which depend on that by implementing one or > more of the weak functions, there is also a bunch of drivers which relies > on the weak functions which invoke msi_controller::setup_irq[s] and > msi_controller::teardown_irq. > > Make the architectures and drivers which rely on them select them in Kconfig > and if not selected replace them by stub functions which emit a warning and > fail the PCI/MSI interrupt allocation. > > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Today's linux-next will have some warnings on s390x: .config: https://gitlab.com/cailca/linux-mm/-/blob/master/s390.config WARNING: unmet direct dependencies detected for PCI_MSI_ARCH_FALLBACKS Depends on [n]: PCI [=n] Selected by [y]: - S390 [=y] WARNING: unmet direct dependencies detected for PCI_MSI_ARCH_FALLBACKS Depends on [n]: PCI [=n] Selected by [y]: - S390 [=y] > --- > V2: Make the architectures (and drivers) which need the fallbacks select them > and not the other way round (Bjorn). > --- > arch/ia64/Kconfig | 1 + > arch/mips/Kconfig | 1 + > arch/powerpc/Kconfig | 1 + > arch/s390/Kconfig | 1 + > arch/sparc/Kconfig | 1 + > arch/x86/Kconfig | 1 + > drivers/pci/Kconfig | 3 +++ > drivers/pci/controller/Kconfig | 3 +++ > drivers/pci/msi.c | 3 ++- > include/linux/msi.h | 31 ++++++++++++++++++++++++++----- > 10 files changed, 40 insertions(+), 6 deletions(-) > > --- a/arch/ia64/Kconfig > +++ b/arch/ia64/Kconfig > @@ -56,6 +56,7 @@ config IA64 > select NEED_DMA_MAP_STATE > select NEED_SG_DMA_LENGTH > select NUMA if !FLATMEM > + select PCI_MSI_ARCH_FALLBACKS > default y > help > The Itanium Processor Family is Intel's 64-bit successor to > --- a/arch/mips/Kconfig > +++ b/arch/mips/Kconfig > @@ -86,6 +86,7 @@ config MIPS > select MODULES_USE_ELF_REL if MODULES > select MODULES_USE_ELF_RELA if MODULES && 64BIT > select PERF_USE_VMALLOC > + select PCI_MSI_ARCH_FALLBACKS > select RTC_LIB > select SYSCTL_EXCEPTION_TRACE > select VIRT_TO_BUS > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -246,6 +246,7 @@ config PPC > select OLD_SIGACTION if PPC32 > select OLD_SIGSUSPEND > select PCI_DOMAINS if PCI > + select PCI_MSI_ARCH_FALLBACKS > select PCI_SYSCALL if PCI > select PPC_DAWR if PPC64 > select RTC_LIB > --- a/arch/s390/Kconfig > +++ b/arch/s390/Kconfig > @@ -185,6 +185,7 @@ config S390 > select OLD_SIGSUSPEND3 > select PCI_DOMAINS if PCI > select PCI_MSI if PCI > + select PCI_MSI_ARCH_FALLBACKS > select SPARSE_IRQ > select SYSCTL_EXCEPTION_TRACE > select THREAD_INFO_IN_TASK > --- a/arch/sparc/Kconfig > +++ b/arch/sparc/Kconfig > @@ -43,6 +43,7 @@ config SPARC > select GENERIC_STRNLEN_USER > select MODULES_USE_ELF_RELA > select PCI_SYSCALL if PCI > + select PCI_MSI_ARCH_FALLBACKS > select ODD_RT_SIGACTION > select OLD_SIGSUSPEND > select CPU_NO_EFFICIENT_FFS > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -225,6 +225,7 @@ config X86 > select NEED_SG_DMA_LENGTH > select PCI_DOMAINS if PCI > select PCI_LOCKLESS_CONFIG if PCI > + select PCI_MSI_ARCH_FALLBACKS > select PERF_EVENTS > select RTC_LIB > select RTC_MC146818_LIB > --- a/drivers/pci/Kconfig > +++ b/drivers/pci/Kconfig > @@ -56,6 +56,9 @@ config PCI_MSI_IRQ_DOMAIN > depends on PCI_MSI > select GENERIC_MSI_IRQ_DOMAIN > > +config PCI_MSI_ARCH_FALLBACKS > + bool > + > config PCI_QUIRKS > default y > bool "Enable PCI quirk workarounds" if EXPERT > --- a/drivers/pci/controller/Kconfig > +++ b/drivers/pci/controller/Kconfig > @@ -41,6 +41,7 @@ config PCI_TEGRA > bool "NVIDIA Tegra PCIe controller" > depends on ARCH_TEGRA || COMPILE_TEST > depends on PCI_MSI_IRQ_DOMAIN > + select PCI_MSI_ARCH_FALLBACKS > help > Say Y here if you want support for the PCIe host controller found > on NVIDIA Tegra SoCs. > @@ -67,6 +68,7 @@ config PCIE_RCAR_HOST > bool "Renesas R-Car PCIe host controller" > depends on ARCH_RENESAS || COMPILE_TEST > depends on PCI_MSI_IRQ_DOMAIN > + select PCI_MSI_ARCH_FALLBACKS > help > Say Y here if you want PCIe controller support on R-Car SoCs in host > mode. > @@ -103,6 +105,7 @@ config PCIE_XILINX_CPM > bool "Xilinx Versal CPM host bridge support" > depends on ARCH_ZYNQMP || COMPILE_TEST > select PCI_HOST_COMMON > + select PCI_MSI_ARCH_FALLBACKS > help > Say 'Y' here if you want kernel support for the > Xilinx Versal CPM host bridge. > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -58,8 +58,8 @@ static void pci_msi_teardown_msi_irqs(st > #define pci_msi_teardown_msi_irqs arch_teardown_msi_irqs > #endif > > +#ifdef CONFIG_PCI_MSI_ARCH_FALLBACKS > /* Arch hooks */ > - > int __weak arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc) > { > struct msi_controller *chip = dev->bus->msi; > @@ -132,6 +132,7 @@ void __weak arch_teardown_msi_irqs(struc > { > return default_teardown_msi_irqs(dev); > } > +#endif /* CONFIG_PCI_MSI_ARCH_FALLBACKS */ > > static void default_restore_msi_irq(struct pci_dev *dev, int irq) > { > --- a/include/linux/msi.h > +++ b/include/linux/msi.h > @@ -193,17 +193,38 @@ void pci_msi_mask_irq(struct irq_data *d > void pci_msi_unmask_irq(struct irq_data *data); > > /* > - * The arch hooks to setup up msi irqs. Those functions are > - * implemented as weak symbols so that they /can/ be overriden by > - * architecture specific code if needed. > + * The arch hooks to setup up msi irqs. Default functions are implemented > + * as weak symbols so that they /can/ be overriden by architecture specific > + * code if needed. These hooks must be enabled by the architecture or by > + * drivers which depend on them via msi_controller based MSI handling. > + * > + * If CONFIG_PCI_MSI_ARCH_FALLBACKS is not selected they are replaced by > + * stubs with warnings. > */ > +#ifdef CONFIG_PCI_MSI_DISABLE_ARCH_FALLBACKS > int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc); > void arch_teardown_msi_irq(unsigned int irq); > int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type); > void arch_teardown_msi_irqs(struct pci_dev *dev); > -void arch_restore_msi_irqs(struct pci_dev *dev); > - > void default_teardown_msi_irqs(struct pci_dev *dev); > +#else > +static inline int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int > type) > +{ > + WARN_ON_ONCE(1); > + return -ENODEV; > +} > + > +static inline void arch_teardown_msi_irqs(struct pci_dev *dev) > +{ > + WARN_ON_ONCE(1); > +} > +#endif > + > +/* > + * The restore hooks are still available as they are useful even > + * for fully irq domain based setups. Courtesy to XEN/X86. > + */ > +void arch_restore_msi_irqs(struct pci_dev *dev); > void default_restore_msi_irqs(struct pci_dev *dev); > > struct msi_controller { >
